Glycolysis

Question 1

definition of glycolysis

Answer 1

the breakdown of glucose to smaller molecules, so producing. the conversion of glucose to pyruvate

Question 2

where does glycolysis take place

Answer 2

the cytoplasm of cells

Question 3

what are the three chemical groups that come up in metabolism

Answer 3

aldehydes such as acetaldehyde (CH3CHO)
ketones such as acetone (CH3COCH3)
carboxyl groups such as acetic acid (CH3COOH)

Question 4

what is the ending which denotes sugar

Answer 4

-ose

Question 5

what is glucose also known as

Answer 5

hexose as it has six carbons (6 membered pyranose ring) , therefore one with three carbons would be known as triode and so on

Question 6

what is important to remember about molecules

Answer 6

there is less space in molecules than would appear from the standard way they are represented

Question 7

structure of fructose

Answer 7

froms a 5-membered (furanose) ring

Question 8

what acids are common in metabolism

Answer 8

keto acids

Question 9

Transamination

Answer 9

a chemical reaction that transfers an amino group to a ketoacid to form new amino acids

Question 10

what makes up an amino acid

Answer 10

they have an amino group and an acid group and an R group, the amino group joins to the carboxyl group of its neighbour forming a peptide bond

Question 11

Whats the first stage of glycolysis

Answer 11

phosphorylation:
this is the stage that consumes ATP
it traps glucose in the cell because glucose-6-P is ionised and unable to cross the cell membrane

Question 12

What is the second stage of glycolysis

Answer 12

isomerization:

glucose-6-P is converted to fructose-6-P (these have the same molecular formula C6H12O6)

Question 13

What is the third stage of glycolysis

Answer 13

another stage of phosphorylation:
again consuming ATP
it forms a hexose diphosphate that can be split into two phophorlytaed 3-carbon compounds
Fructose 1,6 - biphospahte

Question 14

What is the fourth stage of glycolysis

Answer 14

cleavage + isomerization:
this forms two phosphorylated carbon compounds, then allows dihydroxyacetone-P to be converted to glyceraldehyde-3-P which can be metabolised

Question 15

What is the 5th stage of glycolysis

Answer 15

oxidative phosphorylation:
gylceraldehyde-3-P is simultaneously oxidised and phosphorylated.
The hydrogen and electrons from glyceraldehyde-3-P are passed to nicotinamide adenine dinucleotide (NAD+)

Question 16

In NAD what does R=

Answer 16

H

Question 17

in NADP what does R=

Answer 17

Phosphate

Question 18

Whats the role of vitamin B3 (niacin)

Answer 18

provides the nicotinamide part of the NAD+ molecule

needs to be provided in the diet

Question 19

Lack of niacin causes what

Answer 19

pellagra - sensitivity to sunlight, dermatitis, alopecia, glossitis, weakness and ataxia (lack of muscle coordination)

Question 20

What is the 6th stage in glycolysis

Answer 20

transfer of phosphate:
ATP PRODUCTION
2 molecules of ATP produced per molecule of glucose are consumed

Question 21

What is the 7th stage

Answer 21

molecular rearrangement:

phosphate group moved from one position to another (isomerization)

Question 22

What is the 8th stage

Answer 22

dehydration:

favours transfer of phosphate to ATP

Question 23

What is the 9th stage

Answer 23

transfer of phosphate:

2 molecules of ATP Produced for every molecule of glucose consumed

Question 24

Once this cycle is complete what happens under aerobic conditions

Answer 24

NAH+ is regenerated because NADH passes the electrons and the hydrogen atoms which recieves from glyceraldehyde-3-P though a system known as the electron transfer chain which combines therewith molecular oxygen to form water (also generates ATP)

Question 25

Once this cycle is complete what happens under anerobic conditions (absence of molecular oxygen)

Answer 25

NADH builds up because NAD+ cannot be regenerated

if persisted glycolysis HALTS

Question 26

How is NADH re-oxidised

Answer 26

by reducing pyruvate to lactate (this is responsible for muscle aches SPAGIE)

Question 27

How does yeast get over the problem of anaerobic respiration

Answer 27

to regenerate NAH+ it converts pyruvate into ethanol

Question 28

What are the three enzymes which regulate glycolysis

Answer 28

Hexokinase
Phosphofructokinase
Pyruvate kinase

Question 29

Hexokinase

Answer 29

Catalyses: glucose → glucose-6-P)

Question 30

Phosphofructokinase

Answer 30

Catalyses: fructose-6-P → fructose-1,6- bisphosphate

Question 31

Pyruvate kinase

Answer 31

Catalyses: phosphoenolpyruvate → pyruvate

Question 32

Major roles of phosphofructokinase

Answer 32

1. High ATP allosterically inhibits the enzyme
2. Low pH inhibits the enzyme (lactate accumulation)
3. High citric aid inhibits
4. High fructose-6-P stimulates the enzyme